An Observer vox pop revealed a sophisticated take on summer fashion. James Ronald, 33, from Kettering, Northants, said: "My shirt is from Tokyo, jeans from ASOS and shoes from YMC. People are dressing better in the summertime now because the high street has improved." Photograph: Katherine Rose for the Observer

For all but the most resolutely miserable residents of our green and – now very – pleasant land, the mercury rising to such dizzy heights makes everything seem so much easier, so much more … possible. Waking each morning filled with the natural high that sunlight brings makes even the most arduous of working days a little more appealing.

Until, that is, you are faced with dressing for a day at the office. Opening the wardrobe doors on a sunny weekday morning has long been a proposition that fills men and women alike with dread. As a nation, we have been mocked for our inability to assemble outfits with any semblance of cohesive style once the central heating is turned off and the tweed coats are stored away for a few months. Somehow, the idea of finding a sartorial solution to suit the searing heat has confounded most Britons – until now.

But, as thermometers joyfully announced temperatures of 27C or more this week, there was a noticeable change in workplace attire, and it was definitely for the better. At last, it's safe to declare that we have collectively learned how to dress for summer.

It was refreshing to witness women wending their way to the office looking cool – in both senses of the word. It brought me great joy to see real style statements being made, not just despite the heat, but because of it.

I watched as a pair of 40-something women made their way from a busy West End tube station. One was wearing an asymmetric, dove grey, short-sleeved dress that I recognized as last season COS (the grown-up, avant-garde sister brand of Swedish chain H&M, which owes more than a nod in design terms to Marni), with a pair of heeled, caramel leather gladiator sandals. She carried a capacious leather tote and wore her hair in a neat, sharp bob. Her companion, a little older, wore a pair of extra wide, high-waist navy trousers with a crisp buttermilk cotton shirt and a pair of cream leather brogues on sockless feet. She carried an Old Skool red leather satchel, and wore her long, greying hair in a sleek ponytail – all very Margaret Howell. Both looked professional, polished and unruffled by the clammy weather. Granted, they are at the upper end of the style spectrum, and were probably headed for a design studio or PR office, but they weren't alone in their efforts to adapt their signature looks to the sunshine.

All around the capital, women emerged in an array of summer dresses – not sundresses, you understand, but proper dresses with structure, style and more than a slip of a sleeve – accessorized with statement shoes. Some wore super-sheer hosiery, others paraded bare legs – either proudly pale or with a hint of subtle glow courtesy of self tan or an early sojourn in the sun. I saw female commuters, young and old, in chic pencil skirts, worn with billowy silk blouses or draped jersey tops, or in 1950s-style dirndl skirts to the knee with a lightweight cotton cardigan, and kitten-heeled stilettoes.

Men, too, had pulled out the stops. Clearly, many are still bound by strict dress codes issued in the dark ages, whereby a grey worsted wool suit, blue stiff-collar shirt, motif tie and black Derby shoes are a sartorial staple throughout the seasons. But increasingly, we're seeing an ability to break away from long-established edicts pertaining to professional attire in favour of a continental approach to dressing. It is entirely acceptable in 21st-century Britain to abandon the weight of Savile Row-style suiting in favour of the lighter suits favoured by the Spanish, Italian and French, teamed with shirts designed to be worn open at the collar rather than simply unbuttoning their double-cuffed poplin Thomas Pink (and yes, there is a distinct difference).

We have learned the secrets of summer dressing from the global marketplace and those who have traditionally done it better.

Our exposure to long-haul travel has led us to understand that bare flesh is inappropriate in terms of accepted etiquette in certain environments – whether for religious, cultural or simply professional reasons. Inspired by the prevalent dress in hotter regions, many of us have also grasped that stripping off is not the solution when it comes to keeping cool in the heat. There are reasons that djellabahs, kurtas and saris are popular in tropical and equatorial climes (aside from the cultural constraints and religious protocol): the covered-up, relaxed silhouettes and natural fibres keep the sun's rays away from bare flesh and allow circulating air to cool the skin.

We've watched as Queen Rania of Jordan, Christine Lagarde (who has confessed to a penchant for the "wonderful, wearable suits" at Austin Reed), Rachida Dati, Elle Macpherson and Michelle Obama dress for success in the heat. Even our very own style gurus have learned a lesson or two about polished summer dressing: Victoria Beckham, the Duchess of Cambridge and Samantha Cameron have taught us the value of a good dress and quality shoes, or the power of well-chosen, properly-fitting separates. While we don't all wish to look like a political spouse or young royal, the tips have been taken.

The arrival of brands such as Mango, Zara, Banana Republic and Anthropologie on our shores has given access to the sort of summer style that has long delivered cool comfort to our sisters overseas: easy elegance in the form of smart, office-friendly dresses and lighter suits in chic, breathable, crease-resistant synthetics. We have embraced a more sophisticated summer palette of muted neutrals (ivory, navy, khaki, dove grey are all surprisingly complimentary on both pale or sunkissed skin), while we have slowly grown to understand that insipid pastels and ditsy florals are better left for weddings.

British women now know the importance of grooming. It is paramount at all times, but especially so when more of you is on show, when even the most pulled-together of outfits fails if accompanied by unkempt hair, scraggy nails and bruised shins. And you can get away with the simplest of white T-shirts, a plain skirt and sandals if your feet are pedicured, your locks are tamed and your clothes are pressed. There is, of course, wisdom in walking the line between immaculate presentation and the high-maintenance salon obsession that can make you look more showgirl than career girl.

It is disappointing to note that most of the glossy monthly style bibles still address the concept of summer wardrobes as something that solely involves trips to the beach (in either Cornwall, Ibiza, Morocco or some other more exotic destination du jour), glamping, hanging out at one festival or another, or whizzing off on a summer city break. There is little recognition that most of us continue to earn our keep throughout the summer months. Yet, somehow, most of us have muddled through, establishing some kind of modern dress code for days when the sky resembles those famous Tiffany boxes and we can step out without the worry of umbrellas.

I say this with a few caveats, of course. For every handful of stylish summer ensembles making their way to work this week, there was a walking disaster zone of calloused feet and streaky spray-tanned limbs flip-flopping along the pavements beneath a crumpled slip of a dress revealing inadvertent glimpses of breasts or even knickers as they clambered up steps. The fact that the sartorially-challenged stand out, however, suggests they are now the exception rather than the well-dressed norm.

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